Like the Wright brothers, who followed, John Stringfellow and his associate William Henson are an important link to early aeronautical researchers. At an exposition in 1868 in London's Crystal Palace, where it powered a triplane model along a cable, the Aeronautical Society of Great Britain awarded a prize of £100 to Stringfellow’s engine as the lightest in proportion to its power, producing 0.75 kW (one horsepower) for the weight of 5.9 kg (13 pounds).
In 1889, Smithsonian Secretary Samuel P. Langley purchased the engine, along with a "car" designed to carry an engine and a pair of propellers, for £25, and donated it to the museum.
The propellers are fabric covered, having flat cross section blades with fairly extreme pitch and squared off ends. The blades are made of three 0.64 cm (¼-inch) wooden dowels passing through a solid 2.54 cm (one-inch) dowel hub, which formed part of a belt transmission system to the centrally mounted engine.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.